facebook getLogoutUrl returns a URL with access_token=0, when clicked redirects to Facebook user's home page

Question

I'm integrating Facebook with my site and I've added a Logout button whose URL is taken from:

$facebook->getLogoutUrl(array('next' => 'http://mydomain.com/logout.php'));

The problem is that logout.php is never called. Instead, on click of the Logout button, it redirects to the logged-in user's Facebook home page. It doesn't log the user out of Facebook, and it doesn't call my next URL.

I noticed that the URL generated by getLogoutURL() looks like:

https://www.facebook.com/logout.php?next=http://mydomain.com/logout.php&access_token=0

Notice there is an access_token=0. Should that value not be zero? That's the only thing I can think of that might be causing the problem.

I've already set my FB app's Site URL to http://mydomain.com. While testing locally, I've also edited my hosts file. I've also googled a lot and I haven't found a solution. The only one that worked was adding an onclick to my logout button using FB.logout(). But I would need to use PHP.

Any ideas as to why the logout URL is not working?

Answer 1

Okay, I've solved this by creating my own logout URL and adding an access token

$logoutUrl = 'https://www.facebook.com/logout.php?next=http://mydomain.com/logout.php&access_token=' . $facebook->getAccessToken();